Liposomes are spherical vesicles composed of a closed bilayer membrane that entraps part of the surrounding media. They have been used as biocompatible carriers of drugs, peptides, proteins or DNA for pharmaceutical, cosmetic, and biochemical purposes (Allen and Cullis, 2004, Science 303:1818; Ulrich, 2002, Biosci. Rep. 22:129). Peptide amphiphiles (PAs) are comprised of aliphatic chains and oligopeptide head groups (Hartgerink et al., 2002, Proc. Natl. Acad. Sci. 99:5133; Hartgerink et al., 2001, Science 294:1684). Self-assembly of PAs by β-sheet formation of the peptide segments and hydrophobic collapse of the aliphatic chains results in one-dimensional nanofibers or networks thereof to give gels in certain conditions. This PA nanofiber system has shown potential for various applications including regenerative medicine (silva et al., 2004, Science 303:1352), tissue engineering (Beniash et al., 2005, Acta Bio. 1:387) or chemotherapy (Bull et al., 2005, Nano Lett. 5:1) based on the epitopes displayed on the periphery. However, the delivery of therapeutic agents by bare nanostructures would be deleterious to normal tissues, and as such is not a viable alternative for therapeutic treatments like chemotherapy.
As such, what is needed are ways of utilizing emerging technologies such that their therapeutic value is realized.